Recent luminaires employ lamps such as high pressure sodium discharge arc lamps, commonly known as HPS lamps, which are very efficient. Such lamps are designed to operate at a predetermined temperature at which the intended amount of light is produced with the desired spectral characteristics and at which the lamp has a relatively well-known life.
If the operating temperature is increased, not only is the life shortened, but other characteristics can also be changed.
Normally, lamps are used with reflectors, whether the lamps are HPS or some other type. Various kinds of reflectors have been developed to create certain effects with light and for use with certain lamp types. Several examples are found in the following U.S. patents.
______________________________________ U.S. Pat. No. Inventor ______________________________________ 755,196 Wadsworth 4,218,727 Shemitz et al 4,241,393 Olson 3,900,727 Hutz 1,562,502 Gowdy 2,340,515 Dietrich 1,281,752 Bailey 2,913,570 Gough et al 3,329,812 Harling 3,758,770 Morasz 1,698,279 Schimpff 3,102,693 Rex 3,950,638 Kent et al ______________________________________
As will be observed, these patents show devices having various shapes with portions following selected surfaces of revolution, some surfaces having ridges, flutes or grooves and others being smooth.